diff --git a/Algo/Séminaire/Exercices seminaire.md b/Algo/Séminaire/Exercices seminaire.md
index 71fb4e4..347f41c 100644
--- a/Algo/Séminaire/Exercices seminaire.md	
+++ b/Algo/Séminaire/Exercices seminaire.md	
@@ -445,10 +445,15 @@ $$
 = O(log(n))
 $$
 ##  Exercise 4.12 - Prime number
-```Ocaml
+```OCaml
 let prime n =
 	if n < 1 then
 		invalid_args "n should not be inferior to zero"
 	else if x = 2 then true
 	else 
-		let rec pr a 
+		let rec pr n k =
+			if n mod k = 0 then
+				false
+			else
+				check n (k + 1)
+		in pr n 2;;